One of the most fascinating styles found in glassblowing these days is the use of dichroic glass. You very well may be familiar with dichroic glass, or maybe you’ve seen it before, or you may have no idea what it is. In any case, I hope this’ll teach you at least a little bit more about it, and develop your appreciation for this metallic layering. It’s a mysterious little type of glass that sort of screws with you when you see it, because it appears to be two different colors. Actually, the word “dichroic” was formed after the Greek word dikhroos, which literally translates to “two colored”. This phenomenon is used in a multitude of industries for both practical purposes and its mesmerizing effect. The unique light filtering properties of dichroic glass have been used since the ancient Greek Empire, but had had little use until that last half century or so.
Dichroic glass was only brought back to popularity and actual use by none other than NASA. When the space organization developed plans to send man to the moon In the 1950s and ‘60s, they needed to find a way to shield their delicate spacecraft from the sun. That’s where dichroic filtering came in.
NASA’s use of dichroic glass perfectly demonstrates the theory of dichroism: thin layers of crystalline metals and silicates transmit some wavelengths while reflecting others. Knowing the wavelength of the sun’s rays, NASA figured out how to engineer dichroic glass to reflect destructively hot solar rays as opposed to absorbing them, keeping their spacecraft free of radiation damage. This discovery by NASA got the ball rolling when it came to dichro in the artistic glass movement. A man named Jerry Sandberg is credited with bringing dichro to glass art industry, after he pioneered a vacuum depositing vaporizer. Sandberg later met another person in particular who deserves credit when it comes to popularizing dichroic glass: Murray Schwartz, who worked with NASA as an aerospace engineer developing dichroic filters. Schwartz ended up experimenting with dichroic glass after his work with NASA as he became fascinated with the unique beauty of dichroic films and their use in so called “chameleon glass” (named for its color-changing ability).
NASA Experiments with Layered Dichroic Filters
This person is holding single sheet of dichroic film.
Notice how different shades of blue and gold can be seen in the sheet.
“I was very much interested in thin film physics, and I also had a keen attraction to dichroic glass, which, in the purity of its narrow bands of color, is overwhelmingly beautiful. When coupled with the feature of colors that change, the material is quite fascinating, almost magical, and certainly appealing. So I decided to make a little
business out of it." – Murray Schwartz
Schwartz started a dichroic art company in the early ‘70s called Kroma Glass, which has created a number of highly sought-after stained glass windows, artistic tables, jewelry and other sculptures. This form of art transferred of course into the glass pipe industry, and has proved to be one of the most high-tech artistic applications in glassblowing.
The process in which dichroic film is deposited onto a glass surface is complicated and technical. To create dichroic glass, an electron beam vaporizes a combination of quartz crystal and metal oxides inside a vacuum, allowing the vapors to float upwards and condense on a glass surface, settling to form a crystalline structure. This dichroic film can be manipulated with incredibly thin layers of metals like gold or silver, and/or oxides of certain metals like titanium, chromium, aluminum, zirconium, magnesium, or silica. Any combination of these metals can be used to create a dichroic filter, in as many as 50 layers in a single dichroic film. To give you an idea of how tiny these metal crystals are, even with 50 layers of metal coatings, the dichro film is hardly 30 millionths of an inch thick. With careful control of thickness and metals used in the filter, a host of beautiful reflective colors can be made. While entire sheets of dichroic film can be used to achieve a desired look, dichroic layers can be applied to any type of glass, including fine grain frit.
Dichroic Glass Sheet
Bubbler by Eusheen & Revere Glass
Bubbler by Turtle Time Glass (above) and detail (below)
In whichever form dichroic layering is used, it’s always strikingly beautiful. Well-incorporated dichroic art can be gripping to the point where you find yourself staring at it from all different angles for a good long while. If your collection is dichro-free, I recommend you change that. Grasscity offers a great selection of dichroic-clad pipes of different shapes and sizes. Be on the lookout for this unique multifaceted material; it just may be the clinching factor in whether or not you decide to pick up your new artistic glass piece.